German patent application DE-A-2851333 shows a vehicle safety device that uses electrically actuated tripping devices to actuate a passenger restraint device, such as an air bag. The tripping devices are typically ignition tablets. When electric current flows through an ignition tablet, the tablet ignites and thus actuates the restraint device. If the main power source for the safety device is disconnected during a collision, for example, an electric storage device supplies electric current to ignite the ignition tablet.
Our problem with such known safety devices, is that ignition tablets frequently shunt; that is, once the ignition table is ignited, it is not completely destroyed. As a result, electric current continues to flow through the ignition tablet. This problem is particularly critical if the main power source is disconnected and several ignition tablets must be ignited one after the other by the storage device. If one of the ignition tablets shunts, it can drain the energy from the storage device before the remaining ignition tablets are ignited. As a result, the remaining restraint devices, such as air bags, cannot be actuated to protect the passengers in the vehicle.
The solution of the present invention avoids the disadvantages of shunts occurring in actuated tripping devices to reliably actuate additional tripping devices, despite the limited energy reserve of a storage device.